<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Flask App</title>
</head>
<body>
    {% if url %}
        <a href="{{ url|safe }}">点击这里访问链接</a>
    {% else %}
        <p>没有可用的链接。</p>
    {% endif %}
</body>
</html>